Question 1

Which of the following best explains why eukaryotic gene regulation is generally more complex than prokaryotic gene regulation?

Accepted Answer

Eukaryotic DNA is associated with histones and packaged into chromatin, requiring additional regulatory mechanisms for gene accessibility.

Question 2

Which chromatin modification is most directly associated with increased transcriptional activity in eukaryotes?

Accepted Answer

Histone acetylation by histone acetyltransferases (HATs)

Question 3

A mutation eliminates the TATA box from a gene's core promoter. Which of the following is the most likely consequence?

Accepted Answer

The gene may still be transcribed if other core promoter elements (such as Inr or DPE) are present.

Question 4

Which of the following best describes the function of the SWI/SNF complex?

Accepted Answer

It uses ATP to reposition or remove nucleosomes, increasing DNA accessibility.

Question 5

In the yeast GAL gene system, what is the role of GAL80?

Accepted Answer

It binds to GAL4 and inhibits its activation domain, repressing transcription.

Question 6

Which of the following statements about DNA methylation in mammals is correct?

Accepted Answer

DNA methylation at promoter CpG islands is often associated with transcriptional repression.

Question 7

A gene contains binding sites for both activators and repressors. Which concept does this illustrate?

Accepted Answer

Combinatorial control of transcription

Question 8

Which of the following is a key difference between general and specific transcription factors in eukaryotes?

Accepted Answer

General transcription factors are required for basal transcription at all Pol II promoters, while specific transcription factors regulate transcription in response to signals.

Question 9

Which of the following best describes the function of an insulator element in eukaryotic gene regulation?

Accepted Answer

It blocks the interaction between an enhancer and a non-target promoter.

Question 10

Which of the following is a direct effect of histone acetylation on chromatin structure?

Accepted Answer

Reduces the positive charge on histones, loosening DNA binding and increasing accessibility

Question 11

A researcher inserts a yeast UAS (upstream activating sequence) upstream of a heterologous promoter in yeast. What is the most likely outcome?

Accepted Answer

The UAS can activate transcription from the heterologous promoter, regardless of its distance or orientation (within certain limits).

Question 12

Which of the following best describes the role of the Mediator complex in eukaryotic transcription?

Accepted Answer

It acts as a coactivator, connecting DNA-bound activators to the RNA polymerase II machinery.

Question 13

Which of the following is a characteristic of focused promoters in eukaryotes?

Accepted Answer

They direct transcription initiation at a single major site or within a narrow region.

Question 14

Which of the following best explains how the presence of glucose represses the GAL genes in yeast?

Accepted Answer

Mig1 accumulates and recruits the Cyc8–Tup1 complex, which inhibits coactivators and the initiation machinery required for GAL gene transcription.

Question 15

Which of the following is NOT a function of ATP-dependent chromatin remodeling complexes?

Accepted Answer

Directly synthesizing mRNA from DNA

Question 16

A mutation in a gene's enhancer element is most likely to affect which aspect of gene expression?

Accepted Answer

The efficiency or frequency of transcription initiation

Question 17

Which of the following best describes the relationship between DNA methylation and histone deacetylation in transcriptional repression?

Accepted Answer

DNA methylation recruits methyl-CpG-binding proteins, which can recruit histone deacetylases to promote repressive chromatin.

Question 18

Which of the following is a direct consequence of nucleosome repositioning by chromatin remodelers?

Accepted Answer

Increased accessibility of promoter DNA to transcription factors

Question 19

Which of the following statements about the DNA-binding and activation domains of transcription factors is correct?

Accepted Answer

The DNA-binding domain recognizes specific DNA sequences, while the activation domain interacts with cofactors to regulate transcription.

Transcriptional Regulation in Eukaryotes: Mechanisms, Chromatin, and the GAL Gene System

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